Characterization of Border Trap Density With the Multifrequency Charge Pumping Technique in Dual-Layer Gate Oxide

The multifrequency charge pumping (MFCP) experiments have been investigated by many research groups for the characterization of oxide traps in high-permittivity (high-κ ) dielectric metal-oxide-semiconductor field-effect transistor samples. In these previous studies, the duty cycle was changed for control of charging and discharging depths. In this paper, the spatial and energy distributions of border traps in the metal gate/high-κ dielectric/silicon dioxide (SiO₂) interfacial layer stack structure were characterized as a three-dimensional (3-D) mesh profile by using the MFCP technique. The presented MFCP technique was based on the frequency of the gate pulse in conjunction with the tunneling model of trapped charges and was not the duty cycle. The methodological basis and the accurate model were introduced for the analysis of the measured MFCP data in dual-layer gate oxide. The low-frequency noise measurement and the MFCP technique were used for the analysis of the constant gate bias stress induced trap generation, and the 3-D mesh profile of generating trap density was presented. Moreover, the energy distribution of stress-induced traps was investigated within high-κ, SiO₂, and high-κ/SiO₂ interface.